Dual hook clamp

ABSTRACT

A hook clamp has surfaces allowing the clamp to be placed on a support and clamped thereto. The surfaces are such that the clamp can be placed on the support and its weight held by the support prior to tightening. The clamp has a built-in connector for supplying power to the lamp. The clamp has one or more fail-safe holes for securing the clamp to the support with a safety cable. The clamp also has one or more flanges that can be received by a separate mounting bracket, for mounting the clamp and any attached element during storage, staging, or when otherwise not being used.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation application of and claimspriority to U.S. application Ser. No. 09/779,194, filed on Feb. 7, 2001,which claims the benefit of U.S. Provisional Application Serial No.60/181,455 filed Feb. 10, 2000.

FIELD OF THE INVENTION

[0002] The present invention relates to a clamp for holding astage-mounted device relative to a stage support truss. Morespecifically, the present invention defines a hook clamp, which holdsthe weight and position of the stage-mounted device while it is beingmounted to the support truss, and also has an electrical connectorextending through the clamp.

BACKGROUND AND SUMMARY

[0003] Many stage-mounted devices require a stable base of support.Moving stage lights are often particularly sensitive to suchrequirements. Typically, moving lights are electronically controllableto move between various positions and to provide special effects. Theposition of a moving light, however, is accurate only when the systemhas a very stable base of support. Moreover, because of the lamp size,cooling requirements, and complicated electronics, these lamp devicescan be very heavy. Many times such lights are mounted at the upper areaof the stage, very high off the ground.

[0004] Many lamp clamps are known in the art. Some of the commonly usedones are described herein. A Cheeseborough clamp (U.S. terminology) orScaff clamp (U.K. terminology) is shown in FIG. 1. The clamp 100 isshown in its open position in FIG. 1. The moving part 122 of the clamppivots around pivot point 104 to form a closed clamp as shown in FIG. 2which closes around the supporting pole or pipe. The clamp can betightened by tightening bolt 106 relative to bolt accepting mechanism108, which can be a slot or the like in a plate. The appropriatetightening reduces the size of the inner surfaces, to tighten the clampand to maintain the lamp in position relative to pole 200.

[0005] The inventors of the present invention recognized that thissystem is very difficult for the installers to use. One main reason isbecause the entire weight of the lamp must be supported by the installerwhile attaching the lamp to the pole 200. FIGS. 1 and 2 show theseclamps in the open and closed position, respectively to demonstrate theinstallation. In order to install the lamp, the installer must hold lamp110 while placing the open clamp 100 against pole 200 and while holdingsurface 120 of the open clamp against the supporting pole 200. The clampis hinged around pivot 104 to form a cylindrical inner area 205, asshown in FIG. 2. Bolt 106 holds relative to bolt accepting element 108.

[0006] In order for the lamp to be properly attached to the supportingpole 200, therefore, the bolt 106 must be screwed into the acceptingelement 108 (e.g., a nut or a split holder). Alternately, a wing nut orlike mechanism, on element 108 can be screwed into bolt 106. In any ofthose cases, the installer must hold the weight of the lamp, which canbe as heavy as 60 pounds, while holding the clamp closed andsimultaneously screwing the nut into place. Moreover, even once the nutis screwed into place, the lamp is still not maintained in its properposition relative to the pole until the nut and screw 106, 108 areproperly tightened.

[0007] These most-common kind of lamp clamps have been recognized by theinventors of the present invention to cause problems, making the lampsvery difficult to install.

[0008] A second kind of mounting mechanism is shown in FIG. 3. The lamp110 is connected to a folded piece of metal 300, which includesvertically extending portions 302 and 304, and a horizontal portion 306.The inside surface 308 of clamp 300 is placed against the supportingpipe 200. Since the metal 300 is formed of folded flattened metalsheets, the inside surface 308 touches the pole 200 only at tangentpoints between the flat surfaces and the round pipe, such as 310.Rotation of lamp 110 relative to pole 200 is prevented by tightening setscrew 312 against point of contact 314 on the pole 200.

[0009] There are still problems with this system. Significantly, thissystem allows the weight of the lamp to be placed on the pole prior totightening the set screw 312. However, the lamp can still rotaterelative to the pole, at least until the set screw is tightened againstthe pole. Moreover, this design tends to distort the roundness of thepole because of the large amount of force at the location 314 where theset screw 312 touches the pole. As can easily be seen, moreover, thesystem is inherently unbalanced.

[0010] A different, but similar kind of prior art clamp is shown in FIG.3A. That clamp includes the same basic structure as shown in FIG. 3. Itincludes the set screw 312 which presses against a portion of thesupport pole 200. Ridges 350 and 352 provide extra friction to hold thelamp relative to the pole.

[0011] Power must also be applied to the lamp. Typically the powertravels either along the pole or along a separate conduit, which is nearthe pole. The inventors of the present invention have recognized theinconveniences and difficulties, which often occur in getting the powerto the lamp.

[0012] Since the lamps are very heavy, it is also important to ensurethat the lamp does not fall from its position on the pole. Accidents canhappen, for example, if a technician fails to properly secure the lampto the pole, or if the securing mechanism fails. Such accidents riskboth damage to very expensive equipment, as well as a serious threat tostage workers. One aspect of the present invention proposed a fail-safemechanism for a lamp.

[0013] It is also desirable that the lamp mounting mechanism beversatile in its selection of mounting techniques. One particularlyinteresting mounting technique is a floor mounting. This technique usesa plate or other support base holding special flanges on the clamp.Those flanges position the lamp and clamp “upside down” relative to theposition in which the lamp would be if pole mounted.

[0014] It is an object of the present invention to provide a clamp whichallows flexibility and safety by special techniques which can be usedindividually or in combination. This is done according to the presentinvention by providing an element, which has interior surfaces definingan area which approximates in shape the outer surface of the supportingtruss, over at least over half of the outer surface of the trusssupport. This ensures maximal frictional contact between the support andthe clamp. This friction maintains the lamp in its proper positionrelative to the truss, even prior to frictional tightening.

[0015] A movable element tightens a tightening device into contact withthe support element to further maintain the lamp in position. Theinventor recognized that the combination of an inner surfaceapproximating the outer surface of the support pole, and a design thatallows hooking over the support pole produces a much easier-to-usesystem.

[0016] Structure is provided in the clamp that facilitates thechannelling of power to the lamp. One aspect of this invention includesa special structure incorporated within the clamp which facilitatespower routing to the lamp. This structure includes surfaces defining aspecial hole in a special location on the clamp. A special connectorreceives power and routes the power to a power conduit. That powerconduit is routed around the rear of the connector through another holeand into the lamp. This aspect facilitates application of power to thelamp without the need to provide a separate external power conduit.

[0017] Another feature of the present invention uses a fail-safemechanism, which allows a safety cable through the clamp and around thepole. A technician mounting the lamp can initially connect the safetycable to avoid the lamp falling or the like while it is being installed.

[0018] Another feature of the present clamp provides two separatemounting surfaces: a first surface which allows connection to a supportpole such that the clamp is secured in a first orientation, and a secondsurface which allows connection in a way such that the clamp is securedin a second orientation, different than the first orientation. Thepreferred surfaces include pole mounting surface, mounting the lamp onthe bottom of the clamp, and a floor mounting surface mounting the lampon the top of the clamp.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] These and other aspects of the invention will now be described indetail with reference to the accompanying drawings, wherein:

[0020]FIG. 1 shows a Cheeseborough clamp of the prior art in the openposition;

[0021]FIG. 2 shows the Cheeseborough clamp in the closed position;

[0022]FIG. 3 shows another clamp of the prior art;

[0023]FIG. 3A shows a modification of the FIG. 3 clamp;

[0024]FIG. 4 shows a side view of the clamp of the present invention inthe open position;

[0025]FIG. 5 shows the clamp of the present invention in the closedposition; and

[0026]FIG. 6 shows an exploded view of the clamp of the presentinvention.

[0027]FIG. 7 shows an assembled view of the clamp of the presentinvention.

[0028]FIG. 8 shows a side view of the clamp and interface cable of thepresent invention.

[0029]FIGS. 9A and 9B show an elevated view of the clamp and mountingbracket of the present invention.

[0030]FIG. 10 shows an elevated view of the clamp and mounting bracketof the present invention mated together.

[0031]FIG. 11 shows a dual clamp embodiment;

[0032]FIG. 12 shows a reverse view of the dual clamp embodiment;

[0033]FIG. 13 shows the calibration plate;

[0034]FIG. 14 shows a layout of multiple luminaries.

DESCRIPTION OF THE EMBODIMENTS

[0035]FIG. 4 shows a first embodiment of the invention, which includeslamp 110 connected to the hook clamp 400 of the present embodiment. Moregenerally, any load could be attached to hook clamp 400. Hook clamp 400is adapted to surround a substantially cylindrical support 402 to holdthe weight of lamp 110. Support 402 is conventionally a pole, althoughit could be of any shape.

[0036] The hook clamp includes inner surfaces 404 which aresubstantially the same size and shape as the outer surface 406 of thesupport 402. By this is meant that the inner surfaces are sized andshaped similarly to the support. The shapes are sufficiently similarthat there is a maximal amount of friction between the clamp and supportto keep the clamp in position even prior to tightening. This embodimentattaches to a cylindrical support element 402, and surfaces 404 at leastalong a portion of the clamp are similarly cylindrical. The line 410indicates a dividing line. Inner surfaces 404 above the dividing line410 are cylindrical in shape and of substantially similar shape to theouter surface 406 of the support. The portions between lines 411 and 412are also cylindrical. The pressure of outer surface 406 of pole 402against inner surface 428 of hook portion 430 presses cylinder 402 intocylindrical surface area 422—at least between lines 411 and 412, andmore preferably between lines 409 and 412. The surface 414 preferablyincludes relatively flat surfaces against which the pole is pressedduring the initial time while the hook portion 430 is being secured intoposition over the pole 402.

[0037] The tongue 420 pivots around its pivot point 423, and can bemoved into a position where the inside surface 424 fictionally engagesagainst the support member 402. This final position is shown in FIG. 5,with the surface 424 abutting against the outer surface of the support402. The other surfaces 406 of the support which are above the line 410also abut against the inner surfaces 404 of the internal cylindricalelement. Inner surface 424 of the tongue is preferably concave andsimilar in shape to the outer surface of support 402.

[0038] In operation, the user “opens” the tongue 420 by lowering it toits lowermost position shown in FIG. 4. The user first hooks the deviceover the support member 402. The support member 402 comes in contactwith surface 414. The clamp can slide with the flat surface 414 againstthe pole. The clamp slides until the hooked end 430 is located above andhooked over the top support surface 406. At that time, the outersurfaces 406 of support 402 contact inner surfaces 404 of the clamp 400.The lamp 110 is preferably located at the center of gravity of theclamp, to minimize side-to-side torque on the clamp. The friction of theclose fit between the inner surfaces of the clamp and the outer surfacesof the support pole therefore are preferably sufficient to keep the lampsteady and in position.

[0039] The tongue 420 is then lifted into position, placing the bolt 440into a corresponding notch 442 to close the clamp as shown in FIG. 5.Notch 442 can be formed in hooked end portion 430 or in tongue 420. Whenthe bolt is tightened, it holds the inside surface 424 into closefrictional contact with the support 406. This tightens the clamp aroundthe pole, so that the support is fictionally held by many similar-shapedsurfaces. Since many surfaces of the pole are held, less tightening isnecessary and hence there is less chance of distorting the pole shape.Preferably, many of the parts of the clamp are of similar shape to theouter surface of the pole. All portions above the line 410 are ofsimilar shape, and preferably this is approximately 140° of the circledefined by the cylinder. Preferably all portions between the lines 411and 412 also define arcs which are circular and which hence closelyapproximate the shape of the pole. The position from the left part ofline 410 to the right part of line 412 preferably defines about 250° ofthe circle. An additional 30° or so also has similar shaped elements inthe surface 424. Accordingly, preferably 280° of the circle defined bythe cylinder are substantially the same shape as the surface of thepole. This means that only 80° is not the same shape as the supportpole. Thus {fraction (280/360)}, or approximately 75 percent, of theouter surface of the pole is preferably gripped by similar-shapedsurfaces of the clamp.

[0040] The above-described first embodiment has the significantadvantage of allowing frictional holding of the lamp even prior totightening. This frictional holding, combined with the advantageousstructure of the lamp hook of the present invention keeps the lamphooked in place on the support pole.

[0041] A second embodiment of the present invention includes additionalstructure.

[0042]FIG. 6 shows an exploded view of the multiple parts making up thehook clamp of the second embodiment. It should be understood that theseparts making up the exploded view are also the same parts, which existin the first embodiment. FIG. 7 shows the hook clamp fully assembled.

[0043] The hook clamp body is formed of two bent elements of sheetmetal, including left member 600 and right member 602. Each has a cutoutarea defining a cylindrical surface 404 and defining flat surface 414.Members 600 and 602 are bolted to one another through a rear surfaceelement 604. Element 604 has inner surfaces 606 defining substantially aportion of a cylinder. The hook clamp is bolted together to form anelement having left 600 and right pieces 602, separated by the width ofspacers 605, 611. Spacer elements 605 and 611 are provided between thecentral element 606 and the respective end elements 602 in order toprevent the tongue 420 and bolt 440 from pinching between the sheetmetal elements 600, 602.

[0044] The rear surface element 604 also includes top and bottom splitportions 610 and 612. Each of the split portions includes a movableelement therein which is pivoted about a pivot point. The “top” splitelement 610 includes inner surfaces allowing bolt 440 to pivot therein.Bolt 440 pivots about pivot axis 614 to be swung up and out of the wayfor attachment of the lamp. Bolt 440 is later pivoted into position forsecuring the tongue. Lower split portion 612 includes inner surfacesallowing tongue 420 to pivot relative thereto along the tongue axis 422.

[0045] Tongue 420 also includes split portion 442 having surfaces 620which are pressed against by corresponding surfaces 622 of the bolt.When the bolt 440 is tightened, the surfaces 622 press against thesurfaces 620 to press tongue surfaces 424 closer to the rear surfaces606. This has the effect of reducing the internal surfaces defining thecylindrical grip of the clamp, to thereby press the hook clamp moretightly against the cylindrical support 402.

[0046] The left and right pieces 600 and 602 include mounting holes 640therein, preferably at a center of gravity of the clamp device. Mountingholes 640 receive screws for mounting the lamp 110.

[0047] The inventors of the present invention further recognized thatelectrical connection to the lamp could be facilitated by providing aconnector, which is a integral part of the lamp. This connector portionoperates as shown and explained herein.

[0048] The rear mounting plate 650 includes special inner surfaces 652defining a hole of the proper size to receive a speak-on type connector654. This connector is well known in the art, and is of the typetypically used in the lighting industry. Of course, any suitableconnector could be located in this position. The interface end 656 ofthe speak-on connector receives the power cable to provide power and/orcontrol signals. FIG. 7 shows the exit end 660 providing an output tointerface cable 670. A wiring end 672 of interface cable 670 has itswire elements respectively connected to the connector terminals 662 ofthe connector 654. The interface cable 670 runs along the rear surfaceof the rear surface element 604, and into the inner surface hole ofsliding connector 680.

[0049]FIGS. 7 and 8 show two fail-safe holes 700 and 702 provided inleft and right pieces 600 and 602 respectively. A sturdy safety cablecan be threaded through fail-safe holes 700 and 702 and around thecylindrical support 402 (or through some fixture attached to the lamppole), to secure the hook clamp 400 to the cylindrical support 402, evenif its tongue 420 is not yet secured against support 402. This allows atechnician installing the lamp to secure the hook clamp and lampassembly to the pole with a safety cable through at least one of theholes and around the supporting pole 402. The cable can remain securingthe lamp and hook clamp, even in the event of any failure of the hookclamp mechanism.

[0050] A particularly preferred and alternative embodiment of theinvention enables an alternative mounting mechanism for the hook clamp.The left and right pieces of the hook clamp 602 are formed with specialmounting flanges shown as 702, 704. The otherwise planar end pieces 602,604, have mounting flanges, which extend in a perpendicular direction tothe plane formed by the left and right pieces. Those mounted flanges canbe used for an alternative mounting system which is shown in FIGS. 9A,9B and 10. The hook clamp is shown in FIG. 9A, mounted in an upside downposition as compared with the position of pole mounting. In thisposition, the flange surfaces 704, 706 hold the hook clamp in place, ascompared with the normal position in which the inside surfaces 404, etc.hold the hook clamp in place. The flange 704, 706 have respective outersurfaces 708 which are held by a clamping mechanism 900. The clampingmechanism 900 includes clamping surfaces 901 which respectively clampagainst the clamped surfaces 706 of the hook clamp.

[0051] Clamping plate 902 includes a plurality of tightenable bolts 904,and a plurality of fixed bolts 906. When bolts 904 are loosened, theclamp 904 pivots relative to the fixed bolts 906. The clamping surfaceof clamp 900 at end 910 can be lifted up slightly from the underlyingsupport 912. The end 910 preferably includes an upwardly extendingflange, which slips over the clamping surfaces 708. This facilitateslocating the surfaces 708 into their proper location. The entireclamping surface 901 of the clamp can be lifted slightly from theunderlying surface 912. Once the clamping surfaces 708 are located intotheir proper position, the tightenable bolts 904 are tightened tothereby tightly press the tightening surfaces 901 against thecorresponding tightening surfaces 708. The clamp in place is shown inFIG. 10. Note that the clamp surfaces hold the supporting pole in thesame way as in the other manner of tightening. Moreover, the tongueportions are omitted from the FIGS. 9A, 9B and 10 figures, however, itshould be understood that these tongue portions would preferably holdthe lamp into place.

[0052] An important feature of this alternative embodiment is itsability to allow the lamp to be mounted into two different mountinglocations using the same mounting structure.

[0053] A dual hook clamp embodiment is shown in FIG. 11. This embodimentshows a dual hook clamp assembly 1100, with a special carrying handle1105. The clamp assembly can also be rotated in special ways.

[0054]FIG. 11 shows an electrical connection. Cables 1110 and 1115 arethe main cables in the lamp which receive power, data, and diagnostics,and are routed through the hook clamp assembly 1100, through centralaperture 1130, and down into the main lamp assembly. The rear housingpart 1120 has connector mounting apertures for mounting connectors whichare permanently attached to cables 1110 and 1115. External cables withappropriate mating connectors can the be plugged into the permanentlymounted connectors in the hook clamp, thereby providing easily removablepower, data and diagnostics connections to the lamp.

[0055] The clamp assembly includes two hook clamps 1140 and 1150, eachof which has the configuration described above. Specifically, each hasinner surfaces defining a cylinder, and a tightenable tongue.

[0056]FIG. 12 shows an arrangement of the hook clamp and shows how thedevice is rotatable. A rotation plate 1200, shown in more detail in FIG.13A and 13B, allows setting initial orientation relative to other lampsand thereafter controlling all lamps in a group as though they were thesame.

[0057] Lamps may be oriented in different directions when set up. Forexample, FIG. 14 shows a truss 1400 that has a number of different partswith different orientations relative to one another. Section 1402 makesa 450 angle with section 1404. Hence, the lamp 1403 is set at adifferent angle than the lamp 1405. Similarly, truss sections 1406 and1408 hold lamps 1407 and 1409 that have different angles of orientationrelative to one another. However, in this embodiment, they may all needto be pointed in the same, or a similar direction to one another when intheir “zero” (reset) positions. This orientation allows all the lamps tohave the same range of controlled movement relative to the stage/studioarea during operation.

[0058] An initial orientation of the lamp can be set using the rotationplate 1200. Support bracket 1210 provides structural support for thelamp. Bearings contained within the support bracket 1210 allow thebracket to rotate freely relative to the hook clamp assembly 1100,thereby allowing free rotation of the lamp. However, mechanical endstops e.g. 1201, 1202 contained within the whole assembly restrict therotation of the support bracket relative to the hook clamp assemblywithin a specified range. This is because cables pass through the centeraxis of the assembly and these cables have a limited range of “twist”,so the range of rotation needs to be mechanically restricted.

[0059] In this particular embodiment, the “zero” position of the lamp isdetermined as the midway position between the two end stops, i.e. halfway through the range of rotation, although it could equally be set atone or other end of the rotation range, or any position within therange. Essentially, the “zero” position is a position known to the driveelectronics relative to the mechanical limit of rotation.

[0060]FIG. 12 shows a hook clamp assembly 1100 and a support bracket1210. As previously described, the support bracket 1210, which holds thelamp, is freely rotatable relative to the hook clamp 1100 within thelimits of the end stops contained within the assembly. Rotation plate1200 is held captive within the hook clamp assembly but is able torotate if nut 1220 is loosened. Nut 1220 is threaded onto a bolt whichis fixed into the hook clamp and passes through a radial slot 1230 inthe Rotation Plate 1200. The nut has a bottom surface that, when the nutis tightened, presses against the plate surface 1315 and locks therotation plate in position. The rotation plate 1200 is directly attachedto the mechanical end stops within the assembly via a central shaft, andthe rotational relationship between the rotation plate and the end stopsis permanently fixed. The slot 1230 allows the rotation plate 1200 to berotated relative to the hook clamp 1100 whenever the nut 1220 isloosened. Because the rotation plate is directly and permanentlyattached to the end stops, rotating the rotation plate alters theposition of the end sops relative to the hook clamp 1100 and therebyadjusts the “zero” position of the lamp relative to the hook clamp. Inthis way, the lamp can be adjusted into any rotational orientationrelative to the other lamps on the truss irrespective of the orientationof the hook clamp.

[0061] When the nut is loose, lamp holding part can rotate relative toclamp body 1100. This rotation changes the orientation of the lamprelative to the body. The rotation is shown in FIG. 13B, which shows howthe pan shaft can rotate relative to the body.

[0062] In operation, all lamps in a group, i.e., those that need to becontrolled together, are oriented so that their base position, their“zero” position, is the same. Using the FIG. 14 example, lamp 1405 ismounted with the plate set at −45 degrees, 1403 at zero degrees, 1407 at+45 degrees, and 1409 at 90 degrees. When the plates are mounted in thisway, each of the lamps has a reset position, which is in the samedirection. Therefore, they can be controlled as though they were allmounted, oriented, and facing in the same direction.

[0063] The carrying handle 1105 is installed between the two hooks 1140and 1150, mounted into corresponding holes 1142, 1152 in each one. Thehandle is mounted at a specified location, below and behind any locationthat might cause it to clash with the structure of the truss, eitherduring hanging, or when hung, and thereby not reducing the number ofinstallation possibilities, or restricting the operation of installingthe lamp, compared to if there were no handle present.

[0064] Once the lamp is hung and secured, it can be rotated to a desiredorientation using the rotation plate 1200 and the nut 1200 tightened tosecure the plate and thereby set the “zero” position of the lamp.

[0065] This can facilitate installation, since the same lighting effectcan be obtained by installing on any truss facing in any desireddirection.

[0066] Although only a few embodiments have been described in detailabove, those having ordinary skill in the art will certainly understandthat many modifications are possible in the preferred embodiment withoutdeparting from the teachings thereof.

[0067] All such modifications are intended to be encompassed within thefollowing claims.

What is claimed is:
 1. A device and/or method substantially as shown anddescribed.